Progress in mobile robotics requires the researchers to access and improve all modules that compose the robot, from low-level mechanical components to high-level reasoning systems. This paper presents the development process of the robots built at the Autonomous Systems Lab, EPFL Lausanne, Switzerland. Starting from the mechanical and electrical design up to the application, we show the challenges that needed to be faced as well as the solutions that have been devised. The description covers aspects like the operating system and framework, because of its role in the overall safety and dependability of the whole software system, the research as a precondition for innovative products, and the man-machine interface, which is indispensable for conveying information to the user as well as allowing the user to interact with the robot. The issues that have been faced stem from the hierarchical, layered construction of a complex mechatronic product, where the operation of the machine depends on the smooth cooperation of each layer; In the same way, the overall safety is undermined by the least reliable piece building the system.